1. Field of the Invention
The present invention relates to novel heterocyclic bisphosphonic acid derivatives or pharmaceutically acceptable salts thereof and bone resorption inhibitors containing the compound as an active ingredient.
2. Description of the Related Art
A variety of compounds as bisphosphonic acid derivatives have been synthesized and known. However, the compounds having such a heterocyclic group as is defined by the present invention are novel compounds.
The present inventors found that the compounds represented by the general formula (I) or pharmaceutically acceptable salts thereof are novel compounds and have a bone resorption-inhibitory activity as well as an activity to inhibit hypercalcemia caused by bone resorption from the results of animal tests and thus the present invention was completed.